Exercise 8 - Hovering

GROUND SCHOOL POINTS

Ground Effect

Flight Manual performance charts

  • Hover In Ground Effect
  • Hover Out of Ground Effect

PREPARATORY INSTRUCTION

Aim

For the student to learn how to hover.

Motivation

This is an exercise fundamental to all helicopter operations.

Airmanship

  • Lookout
  • Engine limitations

Teaching Points

    1. The hover:
      1. define hovering as maintaining a constant height and heading over a given ground position;
      2. state the hover height as appropriate to type; and
      3. explain that facing into wind results in the helicopter being easier to control and uses less power.
    2. Explain the effects of controls at the hover
      1. Cyclic
        1. Point out the following:
        2. The cyclic controls disc attitude. A change of disc attitude is followed by a change in fuselage attitude. This results in the helicopter moving over the ground. In some types of helicopter there is appreciable lag in this chain of events.
        3. To regain the hover from movement in any direction, requires two cyclic movements; one to stop the movement, and a second to stabilize the helicopter.
        4. All cyclic movements should be small. Cyclic trim should be employed, if fitted.
      2. Collective
        1. Point out the following:
        2. The collective controls height above ground.
        3. Changes of collective pitch will produce yaw and RPM changes unless prevented.
      3. Throttle
        1. Where appropriate to type, describe the use of the throttle to maintain RPM.
      4. Pedals
        1. Describe the effects of pedal control movements on heading and RPM.
    3. Describe the visual cues used to maintain the hover and stress the importance of looking well ahead of the helicopter.

Confirmation 

PRE-FLIGHT BRIEFING

AIR LESSON
    1. Demonstrate the use of the cyclic at the hover into wind.
    2. Student practice with cyclic only, until a hover can be maintained without excessive effort.
    3. Demonstrate the use of the collective and pedals.
    4. Student practice.
    5. Student practice using all controls.
    6. Demonstrate the differences in power required to hover in and out of wind, ground effect, and over different types of surface (e.g. tarmac, long grass etc.).

POST-FLIGHT DEBRIEFING

TIPS FOR INSTRUCTORS
    1. This exercise demands a high degree of co-ordination and should not be taught until the student has acquired a reasonable state of competence in exercises 1-7. Introducing it earlier than this could lead to frustration and undue fatigue for both student and instructor.
    2. An alternative technique is using slow flight to introduce hovering. This procedure takes the form of low slow flight into wind across a suitable clear area. Speed and height are progressively reduced in successive passes until the helicopter is creeping forward at a walking pace in ground effect, and then momentarily halted before transitioning into forward flight again. These momentary pauses are in fact periods of hovering, however brief, and are gradually extended as competency improves, until prolonged periods of hovering are achieved. This procedure is outlined in Exercise 12.
    3. Whichever technique for teaching the hover is used, the student will generally tend to tire quickly. Air exercises should be kept short and terminated as soon as the first signs of fatigue appear.
    4. Initially the student may not be able to use more than one control at a time, and it may even be necessary to limit the travel of that control.
    5. Allow frequent rest periods to enable the student to relax, and try to practise other exercises or perform other demonstrations to give the student a break from hovering.
    6. Keep a close watch on the temperatures, pressures and wind velocity during prolonged hovering.
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